Levenson C W, Shay N F, Cousins R J
Food Science and Human Nutrition Department, University of Florida, Gainesville 32611.
Biochem J. 1994 Nov 1;303 ( Pt 3)(Pt 3):731-6. doi: 10.1042/bj3030731.
Cysteine-rich intestinal protein (CRIP) is an intestinal Zn(2+)-binding protein containing a single copy of the double Zn(2+)-finger arrangement known as the LIM motif. CRIP is developmentally regulated and can be induced by glucocorticoid hormones during the early suckling period. In this report we show that CRIP mRNA levels are induced by dexamethasone in cultured rat intestinal epithelial cells (IEC-6). Analysis of the 2644 bp of the 5'-flanking region of the CRIP gene revealed that the CRIP promoter lacks classical CAAT and TATA boxes but contains GC-rich regions in the proximal end of the promoter that probably function in transcription initiation. In addition to binding sites for transcription factors such as Sp-1, AP-2, OCT and GATA-2, there are multiple glucocorticoid-response elements. CRIP promoter constructs fused to the chloramphenicol acetyltransferase reporter gene and transfected into IEC-6 cells confirmed glucocorticoid responsiveness and the presence of negative acting elements. Mobility-shift assays revealed the presence of nuclear factors that bind to the CRIP promoter as a result of dexamethasone treatment. These experiments provide the initial data required to explore further the regulation of this tissue-specific developmentally regulated Zn(2+)-finger protein.
富含半胱氨酸的肠蛋白（CRIP）是一种肠道锌结合蛋白，含有一个被称为LIM基序的双锌指排列的单拷贝。CRIP受发育调控，在早期哺乳期间可被糖皮质激素诱导。在本报告中，我们表明地塞米松可在培养的大鼠肠上皮细胞（IEC-6）中诱导CRIP mRNA水平。对CRIP基因5'侧翼区2644 bp的分析表明，CRIP启动子缺乏经典的CAAT盒和TATA盒，但在启动子近端含有富含GC的区域，可能在转录起始中起作用。除了转录因子如Sp-1、AP-2、OCT和GATA-2的结合位点外，还有多个糖皮质激素反应元件。与氯霉素乙酰转移酶报告基因融合并转染到IEC-6细胞中的CRIP启动子构建体证实了糖皮质激素反应性和负性作用元件的存在。凝胶迁移实验揭示了由于地塞米松处理而与CRIP启动子结合的核因子的存在。这些实验提供了进一步探索这种组织特异性发育调控的锌指蛋白调控所需的初始数据。
